The controller according to the present disclosure has particular application for controlling a voltage converter in a power supply for a vacuum pump. However, the controller could find application in a broad range of technical fields.
It is well known to power vacuum pumps from an AC mains supply. However, the AC mains supply conditions differ in different territories and may be supplied with the following conditions: (i) 100-127 Vac RMS, +/−10%, 45-65 Hz; or (ii) 200-240 Vac RMS, +/10%, 45-65 Hz. The different mains supply voltages can prove problematic for systems and apparatus to be used in a variety of territories. If too high a voltage is supplied, the systems and apparatus may be damaged. In order to accommodate the different mains supply conditions, a variety of solutions have been proposed, including:                1. Separate low-voltage and high-voltage variant pumps or pump controllers.        2. Manual voltage selector, which requires customer intervention to be set at the correct voltage.        3. Over designed converter and Inverter Power-Train sub-systems designed to run at the highest possible voltage and current.        4. Active front end devices designed to constantly monitor and output a set voltage.        
However, these manufacturing and design solutions can be expensive to implement and have EMC (Electromagnetic Compatibility) and thermal issues.
It is also known to provide a voltage doubler topology, but the standard approach is to fix the voltage doubler so that it is permanently enabled. Alternatively, a voltage selector switch may be provided to allow a user to select the state of the voltage doubler, i.e. enabled or disabled. If the incorrect state is selected, damage may be caused to the system as a result of the increased voltage supplied.
The present disclosure seeks to address or ameliorate some of the short-comings associated with known techniques.